Login help

My snap has been acting strange for years, I got a new phone years ago and on my new phone it stopped letting me log into my old Snapchat account (it would tell me incorrect password) but it would still let me log in on my old phone. I gave up and just deleted my old account that I could still access on my old phone and made a new account on my new phone.. fast forward years later and I am trying to add my email to my account but it needs a password to do so, when I try my password it says incorrect password still. It also says incorrect password even after updating the password through the app. I’m scared that if I somehow get logged out I won’t be able to log back in